body {
  background-color: skyblue;
}

.content {
  padding-top: 40px;
  min-height: 100vh;

  display: flex;
  flex-flow: row wrap;
  /*justify-content: flex-start;*/
  /*justify-content: space-evenly;*/
  align-items: stretch;
}

.tile {
	background-size: cover;
	/*flex-grow: 1;*/
	/*flex-shrink: 100;*/
  /*flex: 50px 100%;*/
  /*flex: 1 0; 50px;*/
  /*min-height: 50px;*/
  /*max-height: 200px;*/
  flex: 1 100%;
}

.tile:hover {
  opacity: .5;
  /*-webkit-filter: grayscale(100%); /* Safari 6.0 - 9.0 */*/
  /*filter: grayscale(100%);*/
}

.tile a {
  display: inline-block;
  width: 100%;
  height: 100%;
}

.tile a:hover img {
	box-shadow: 0 25px 50px -25px rgba(0, 0, 0, .5) inset; 
}